JAMB Mathematics Past Questions & Answers - Page 306

1,526.

Find the gradient of the line passing through the points P(1, 1) and Q(2, 5).

A.

3

B.

2

C.

5

D.

4

Correct answer is D

Let (x1, y1) = (1, 1) and (x2, y2)= (2, 5)

then gradient m of \(\bar{PQ}\) is

m = \(\frac{y_2 - y_1}{x_2 - x_1}\) = \(\frac{5 - 1}{2 - 1}\)

= \(\frac{4}{1}\)

= 4

1,527.

Find the distance between the points (\(\frac{1}{2}\), \(\frac{1}{2}\)) and (-\(\frac{1}{2}\), -\(\frac{1}{2}\)).

A.

1

B.

0

C.

√3

D.

√2

Correct answer is D

Let D denote the distance between (\(\frac{1}{2}\), -\(\frac{1}{2}\)) then using

D = \(\sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}\)

= \(\sqrt{(-{\frac{1}{2} - \frac{1}{2}})^2 + (-{\frac{1}{2} - \frac{1}{2}})^2}\)

= \(\sqrt{(-1)^2 + (-1)^2}\)

= \(\sqrt{1 + 1}\)

= √2

1,528.

A cylindrical pipe 50m long with radius 7m has one end open. What is the total surface area of the pipe?

A.

749\(\pi\)m2

B.

700\(\pi\)m2

C.

350\(\pi\)m2

D.

98\(\pi\)m2

Correct answer is A

Total surface area of the cylindrical pipe = area of circular base + curved surface area

= \(\pi\)r\(^2\) + 2\(\pi\)rh

= \(\pi\) x 7\(^2\) + 2\(\pi\) x 7 x 50

= 49\(\pi\) + 700\(\pi\)

= 749\(\pi\)m\(^2\)

1,529.

The interior angles of a quadrilateral are (x + 15)°, (2x - 45)°, ( x - 30)° and (x + 10)°. Find the value of the least interior angle.

A.

112o

B.

102o

C.

82o

D.

52o

Correct answer is D

(x + 15)° + (2x - 45)° + (x + 10)° = (2n - 4)90°

when n = 4

x + 15° + 2x - 45° + x - 30° + x + 10° = (2 x 4 - 4) 90°

5x - 50° = (8 - 4)90°

5x - 50° = 4 x 90° = 360°

5x = 360° + 50°

5x = 410°

x = \(\frac{410^o}{5}\)

= 82°

Hence, the value of the least interior angle is (x - 30°)

= (82 - 30)°

= 52°

1,530.

If P = \(\begin{pmatrix} 2 & -3 \\ 1 & 1 \end{pmatrix}\) , what is P\(^-1\)

A.

\(\begin{pmatrix} -{\frac{1}{5}} & -{\frac{3}{5}} \\ -{\frac{1}{5}} & -{\frac{2}{5}} \end{pmatrix}\)

B.

\(\begin{pmatrix} {\frac{1}{5}} & {\frac{3}{5}} \\ {\frac{1}{5}} & {\frac{2}{5}} \end{pmatrix}\)

C.

\(\begin{pmatrix} -{\frac{1}{5}} & {\frac{3}{5}} \\ -{\frac{1}{5}} & {\frac{2}{5}} \end{pmatrix}\)

D.

\(\begin{pmatrix} {\frac{1}{5}} & {\frac{3}{5}} \\ -{\frac{1}{5}} & {\frac{2}{5}} \end{pmatrix}\)

Correct answer is D

P = \(\begin{pmatrix} 2 & -3 \\ 1 & 1 \end{pmatrix}\)

|P| = 2 - 1 x -3 = 5

P-1 = \(\frac{1}{5}\)\(\begin{pmatrix} 1 & 3 \\ -1 & 2 \end{pmatrix}\)

= \(\begin{pmatrix} {\frac{1}{5}} & {\frac{3}{5}} \\ -{\frac{1}{5}} & {\frac{2}{5}} \end{pmatrix}\)